1. Field of the Invention
This invention relates to sorbtion paper and sorbtion means for absorbing fumes and odors normally associated with internal combustion engines or body waste devices such as sanitary napkins and disposable diapers.
2. Prior Art
a. Sorbtion Paper
The use of filter papers to filter both air and liquid components of various energy producing devices are well-known and represent a well-developed art. At the outset, it should be noted that the invention herein is not directed to a filter paper as is described in the prior art but rather this invention relates to a sorbtion paper. One essential distinction which must be noted is that in filter paper it is required that the material to be filtered actually physically pass through the filter paper primarily for the purpose of physically separating solid particles from a gaseous stream. In contrast, in the use of sorbtion paper such complete penetration of the paper substrate is not necessary and mere contact with the paper surface as in a laminar or turbulent flow pattern is all that is required to permit diffusion of gaseous components that a filter would allow to pass.
Furthermore, filter paper and the characteristics required thereof permits a paper density of only approximately 1.0 grams of paper per cubic inch while the apertured structure of the sorbtion paper and device of this invention permit a paper density of up to about 5.0 grams of paper per cubic inch of space. Even more beneficial, the sorbtion paper of this invention as a result of its characteristic better particulate retention permits approximately 30 percent greater activated particle loading than a correspondingly sized section of filter paper resulting in approximately six times the activated particle content per unit volume.
In the manufacture of filter papers of a conventional nature porosity of the final product is extremely important. Porosity of the final filter paper product is directly related to the required flow-through characteristics of the paper which are functionally necessary in filter paper. Previous attempts to incorporate activated material such as charcoal into the fibrous structure of the paper have suffered from this necessary porous nature of the filter paper product. In particular, it is necessary to use a binder material such as starch in the manufacture of filter paper to bind the charcoal particles to the fibrous structure of the base paper material. The result of the use of starch or similar binder materials in attempting to hold the charcoal or other particles in place is that the filter paper has a substantial amount of free, loose activated particulate material. This material is more free to rub off on or even contaminate the material being filtered than is the sorbtion paper of this invention. This is unacceptable in most filtration applications and therefore the use of activated material in filter paper has not previously been commercially successful where porosity of the filter paper is necessary to permit flow through of the stream being filtered.
Distinct from this, in the sorbtion paper of applicants' invention a latex type binder material and preferably an anionic polymeric emulsion is used to maintain the position of the activated particulate material. Thus even though the sorbtion paper of applicants' contains up to about 30 percent more activated material than is found in filter paper the final sorbtion paper product is substantially free from loose, dusty activated particulate material. The use of a starch or starch-like binder material results in an air filter paper which is substantially less flexible than the sorbtion paper product disclosed herein.
Furthermore, filter papers, especially those intended for gas phase applications such as automotive air filters, require high flow rates with minimum pressure drop. In order to permit such flow-through characteristics the fibers should be long and relatively stiff with minimum fibrillation or hydration, which are essentially means for increasing surface area. This permits large, uncluttered pores for easy air passage but also minimizes contact area between fibers thus leading to low paper strength. When binder materials such as starch are used to offset the low strength they must be non-film-forming to avoid blocking the filter pores.
In contrast to filter paper the sorbtion paper of this invention can be made with maximized sorption capabilities by using well fibrillated, or hydrated, fibers to provide good particle retention and good particle distribution. This is, of course, optional and fibers such as that used to make filter paper can be used to make sorbtion paper although the binders available for use in sorbtion paper can in some measure compensate for the general paper weakness. The use of film-forming binders as are described hereinbelow not only gives strength to the sorbtion paper itself but also provides a good matrix to prevent sorbtion particles from breaking loose and permits higher levels of sorbtion particle loading.
Further to the porosity characteristics of filter paper it can be shown that the internal bonding of sorbtion paper is substantially greater than the internal bonding characteristics of filter paper. As a result of this, devices, which are described hereinafter, cannot be made with filter paper and have the same necessary structural integrity that is found with sorbtion paper.
In its broadest scope this embodiment of the applicants' invention relates to a sorbtion paper and device which has been "loaded" with activated sorbtion particles to permit sorbtion and regeneration of the activated particles without the necessity for changing the paper or device. Other patents known to applicants and teaching the production of a loaded sheet and specifically a charcoal loaded sheet include U.S. Pat. No. 3,149,023 and its British equivalents, British Pat. No. 961,636; U.S. Pat. No. 3,253,978, and U.S. Pat. No. 3,594,993. While all of these carbon filled sheet patents relate generally to filtration type charcoal loaded paper the distinctions therefrom are numerous and have been pointed out hereinabove. Specifically, the carbon paper of the prior art is generally specific to filtration means and is not correspondingly related to sorbtion means. In this regard it should be once again emphasized that the sorbtion paper of applicants' invention does not require penetration and flow through characteristics which are required for the functioning of known filtration elements.
b. Sorbtion Paper For Use in Combination with Internal Combustion Engines
Hence the substantial body of prior art which relates to filter papers is not equally applicable to sorbtion papers as among other things the mechanism for cleansing the particular gas or liquid is substantially different. In this regard, one embodiment of the present invention relates generally to a sorbtion medium and is directed, more particularly, to a novel sorbtion paper having improved and unique properties for use as a gas sorbtion medium such as in combination with air filters for the air intake system of internal combustion engines.
While the sorbtion paper of the present invention is not limited to use in air filtration systems for internal combustion engines, this use will be particularly described herein because it emphasizes the problems encountered in providing a suitable air sorbtion medium for use in conjunction with air filtration systems and further emphasizes the unique characteristics of the paper and paper devices of this embodiment of the present invention.
In this preferred embodiment the invention relates to a sorbtion device to control hydrocarbon evaporation losses from automobiles. More particularly, the sorbtion device controls hydrocarbon evaporative loss from the carburetor and/or fuel systems of automobiles, trucks and other motorized vehicles.
It has long been established that automobiles constitute a significant source of atmospheric pollution and contamination, leading to the smog problem in many cities. While the bulk of polluting emissions come from the automobile exhaust in the form of unburned hydrocarbons and nitrogen oxides, unburned hydrocarbons also pass into the atmosphere from the carburetor and fuel systems by evaporation. While the amount may not seem to be great enough in one automobile to cause the owner to think he is suffering from this waste, the compounding of the polluting effect by millions of automobiles has resulted in major problems. In its preferred embodiment the present invention is intended to solve this problem by keeping the unburned hydrocarbons escaping the automobile carburation and fuel systems within acceptable limits.
While this has been recognized as a major problem, earlier attempts to solve this problem have generally resulted in overly sophisticated devices and ones which have in some instances proven to be not commercially practical. See for example U.S. Pat. No. 3,191,587. The most common solution to this well-known problem has been the use of air filters in combination with carburation systems in automobiles. This is exemplified by the following patents, U.S. Pat. Nos. 3,505,795; 3,513,643; and 3,747,303. Other patents known to applicants which have shown other somewhat more elaborate devices, all of which depend ultimately on filter paper would include U.S. Pat. No. 3,628,517; 3,646,731, and 3,730,158.
While other patents such as U.S. Pat. No. 3,747,303 mention the use of certain activated particles such as carbon for use with filtration means the sorbtion paper and device of applicants are thought to be novel and to show unique characteristics for performing desired sorbtion functions when used in conjunction with filtration means as for example in an internal combustion engine.
c. Body Waste Devices
A second preferred embodiment of this invention relates to the use of the activated sorbtion paper of this invention in combination with body waste devices such as sanitary napkins, disposable diapers and the like. In this particular embodiment of the invention it is not necessary that the activated sorbtion paper be configured as an apertured structure as the paper itself provides the most convenient insert for such body waste devices. However, any desired configuration which is acceptable to the overall product design of the body waste device is possible.
It is well known that some menstruating females emit odorous menstrual fluids. Emitted fluids can also rapidly form odorous products on further proteolytic reaction. It is established that some of the most perceptible odors are due to chemically basic amine type compounds, which are volatile. The characteristic amine type odors are embarrassing to menstruating females.
The urine impregnated diapers of infants are well known for having and developing an ammonical odor on storage or on extended periods of use such as overnight. The widespread use of single use, disposable baby diapers is restricted by the persistant ammonical odor of the discarded, used diapers, prior to their final disposal outside the baby's household. In addition, the ammonical urine products can induce a common rash on the baby's torso, due to the alkaline pH of the urine in persistent contact with the baby's skin.
The improved body waste device of this invention alleviates the odor problems outlined above by providing a sorbtion paper insert which absorbs and/or adsorbs many of the undesirable odors characteristic of body waste devices such as sanitary napkins and diapers. Body waste devices of this type are uniformly characterized by being disposable and hence sorbtion paper such as will be described hereinafter which does not chemically react with, modify or deactivate the undesirable fumes can be advantageously used.
Previous attempts to deal with these problems in body waste devices have generally involved an attempt to chemically modify the material used to make the body waste device so as to neutralize the odors present. See for example U.S. Pat. No. 3,340,875 and U.S. Pat. No. 3,794,934. Other approaches to this problem have involved the use of physical barriers and the like to attempt to confine the odors. These previous attempts to deodorize body waste products have been largely commercially unsuccessful for both technical and commercial reasons. Other known prior art which is of interest to this embodiment of this invention includes: U.S. Pat. No. 1,773,956; U.S. Pat. No. 2,960,089; U.S. Pat. No. 3,036,573; U.S. Pat. No. 3,340,875; U.S. Pat. No. 3,430,629; U.S. Pat. No. 3,779,246; and U.S. Pat. No. 3,794,034.
Therefore, it is an object of this invention to provide a sorbtion paper which will adsorb and adsorb vapors and fumes on contact.
It is a further object of this invention to provide a sorbtion paper device which is configured so as to provide maximum flow-through characteristics through channels which permit maximum absorption and adsorption of noxious fumes such as hydrocarbons produced by an automobile's internal combustion engine.
A still further object of this invention is to provide a particular sorbtion device for use in combination with filtration means in an internal combustion engine.
An additional object of this invention is to provide a sorbtion paper inert for use in combination with body waste devices such as sanitary napkins and disposable diapers. These and other object of this invention become apparent from the following description of the preferred embodiments.